Early normalization of Quality of Life predicts later remission in depression: Findings from the CO-MED trial

Background: Although normal Quality of Life (QoL) is the outcome desired by patients, it is unclear if QoL changes early in course of antidepressant treatments are independent of depression severity, and can predict subsequent remission.

Methods: The Quality of Life Inventory was obtained repeatedly in the Combining Medications to Enhance Depression Outcomes trial. Mixed model analyses assessed QoL change. Using population-based norms, participants were grouped as very low, low, or normal QoL at week 4, and association with remission was evaluated.

Results: Overall baseline to week 4 QoL improved significantly (p=0.0015) even after controlling for change in depression severity and baseline variables (gender, age, education, race, ethnicity, income, employment status, anxious features, depression onset before age 18, suicidal ideations, and treatment-arm). At week 4, participants with low and normal QoL had higher unadjusted odds ratio (OR) for remission at 3 months (low QoL OR=2.36, 95% confidence interval (CI)=1.25,4.44; normal QoL OR=2.59, 95% CI=1.53,4.39) and 7 months (low QoL OR=2.07, 95% CI=1.00,4.31; normal QoL OR=3.98, 95% CI=2.06,7.69) compared to those with very low QoL. Remission rates, adjusted for baseline variables, were higher only for participants with normal QoL (3 months OR=2.83, 95% CI=1.42,5.68; 7 months OR=6.10, 95% CI=2.40,15.63).

Limitations: Secondary analysis, short period of assessment for QoL change, remission instead of functional recovery as long-term outcome.

Conclusion: Quality of life improves early, independent of depression severity. Normal QoL at week 4 is associated with 2-6 times higher remission rates. Findings support QoL beyond symptomatic change as a potential mediator of remission.